Field of the Disclosure
Embodiments of the present disclosure generally relate to a rotating control device (RCD) of use in a drilling operation. More specifically, embodiments of the present disclosure relate to an RCD having a partition seal assembly that increases seal performance and life.
Description of the Related Art
Drilling a wellbore for hydrocarbons requires significant expenditures of manpower and equipment. Thus, constant advances are being sought to reduce any downtime of equipment and expedite any repairs that become necessary. Rotating equipment requires maintenance as the drilling environment produces forces, elevated temperatures, and abrasive cuttings detrimental to the longevity of seals, bearings, and packing elements.
Rotating control device (RCD) technology has become an important tool for lowering drilling costs and increasing well productivity, especially in many hard-rock areas and mature oil and gas fields. Lower drilling costs are achieved primarily by faster penetration rates, reduced non-drilling time, and reduced mud volume requirements associated with underbalanced drilling.
RCDs are used as diverters on a wellhead or riser and are to be used with annular and ram blow out preventers, and thus have the ability to seal off pressure from a wellbore with or without tubulars in the wellbore. RCDs provide a rotating seal that allows drilling to proceed with the wellbore under pressure. RCDs create a pressure-tight barrier within the wellhead or riser that enables the containment and diversion of returning fluids, thus forming a line of defense against drilling hazards, such as kicks and shallow gas. RCD's permit closed-loop drilling, which offers environmental, cost, and safety benefits. In the past, wellhead pressure was typically limited to a few hundred PSI. Today, however rotary drilling operations are continued with as much as 2,500 PSI peak wellhead pressure while gas-cut fluid is circulated to the surface.
Rotary seals typically rely on a hydrodynamic film or a self-lubricating material. However, it is well known that the life span of rotary seals within RCD systems is relatively short mainly due to higher pressure and velocity (PV) conditions, and continual operations which cause the rotary seals within the RCD to break down rapidly. The greater the differential pressure and the higher the speed required both cause more stress on the rotary seal. Furthermore, reduced film thicknesses and increased friction lead to rotary seal failure. As such, the life of the rotary seals is relatively short and unpredictable. Furthermore, there is a trend in RCD equipment for higher pressure and higher speeds.
During the drilling operation, drill pipe or tubulars are axially and slidably moved through the RCD of a wellhead or riser. The axial movement of the drill pipe along with other forces experienced in the drilling operation cause wear and tear on the bearing and rotary seal assemblies of the RCD, and the rotary seal assemblies subsequently require repair. Typically, the drill pipe or a portion thereof is pulled from the RCD, and the bearing and rotary seal assembly in the RCD is then released. Thereafter, an air tugger or other lifting means in combination with a tool joint on the drill string can be used to lift the bearing and rotary seal assembly from the RCD. The bearing and rotary seal assembly are replaced or reworked, installed into the RCD, and the drilling operation is then resumed.
Therefore, what is needed in the art is a new and improved apparatus for improving rotary seal life. More specifically, what is needed in the art is an improved RCD apparatus for increasing rotary seal performance.